This invention relates to improved stapling instruments, and more particularly to a surgical skin stapler which may be disposable after a single-use or application.
Modern medical procedures and equipment have led to significant advances in medicine, and there have been many new developments in recent years which have substantially contributed to better health care. One of such developments is the use of a skin stapler and metal staples to close a wound or incision, rather than the more conventional thread sutures for closing incisions in living tissue such as fascia or skin of a patient. Such use of skin staplers and metal staples have clearly demonstrated a reduction in suturing time and thus overall operating time the patient must remain in the operating room under anaesthesia. The various stapling instruments developed and marketed heretofore in the medical profession comprise diverse constructions, such as manual and gas powered instruments, but none are yet widely accepted by all doctors for a number of reasons, such as poor visibility of wound site, cost, reliability, bulkiness, lack of familiarity with the product, clumsiness and/or difficulty in use, mechanical complexity, etc. Other surgical stapling instruments incorporate replaceable staple cartridges which may be changed when all of the staples in a single cartridge are utilized.
For example, U.S. Pat. No. 3,643,851 teaches a skin stapler with a staple cartridge and a trigger activated, gas-powered unit for driving a pusher forward to form the staple about an anvil and to eject same prior to returning automatically to its initial rearward position in the stapler ready for the next stapling cycle or sequence. Such instruments incorporating gas-powered driving means, however, do not lend themselves to wide acceptance as they must use sterilized gas, and must be periodically recharged with fresh pressurized gas cartridges or cylinders and such a maintenance requirement is simply disruptive to a doctor or surgeon. However, disposable gas powered staplers are now currently in use, but they, like any gas powered staplers, do not provide the doctor or surgeon with tactile feedback, unlike manually operated instruments which provide more flexibility in control and feel of staple bending and wound approximation. These gas powered staplers are also expensive and complex in operation.
In another medical stapler disclosed in U.S. Pat. No. 4,109,844, a spring-loaded means constantly urges and advances the staples along an anvil plate independent of the staple driver and the driving mechanism which actuates it. Also, a safety latch means to preclude inadvertent operation of the stapling instrument is provided in the stapler. Nevertheless, even though it employs a rotatable nose portion, its overall configuration, hand grip and vertical orientation to the wound site obstructs one's visability of the work area.
In U.S. Pat. No. 4,043,504, staples are stacked in a track of a removable and/or disposable cartridge and moved by spring means toward an anvil on the stapler. Each staple is shifted from a staple feeding track in the cartridge through a specifically sized window by means of a shifter closing the window to a separately divided staple forming track in the forming chamber which contains a former or driver. This unit further employs plural drive means for the staple feed and staple former and is otherwise complex in construction. In addition, the drive means are oriented perpendicular to the two tracks which have a divider wall therebetween and consequently its mechanical operation is achieved with difficulty and requires considerable space creating a more bulky stapler structure. In this regard, the cartridge of U.S. Pat. No. 4,043,504 is specifically intended to be used with the surgical stapling instrument disclosed in U.S. Pat. No. 4,196,836. This instrument has a handle portion and a straight nose portion rotatively mounted in the handle portion. The nose portion carries the instrument anvil and releasably supports the surgical staple carrying cartridge by means of a resilient latch configured to releasably engage the upper end of the cartridge in such a way as to urge the cartridge into abutment with both the nose portion and the instrument anvil.
U.S. Pat. Nos. 3,819,100, 3,949,924 and the disposable skin stapler covered by U.S. Pat. No. 4,204,623 (identified by the "Auto Suture" registered trademark of U.S. Surgical Corporation) all relate to manually-powered surgical stapling instruments and a staple-carrying cartridge, with a nose portion which is rotatably mounted in a hand-held main body portion so that the stapling angle can be varied without rotating the hand-held position of the stapler. Clutch means are also provided to ensure the staple-advancing drive means is only activated once per stapling operation. One of the disadvantages of the Auto Suture stapler is that its trigger is difficult to pull and it can inadvertently pinch flesh, fingers and linen or other items between the trigger and handle in certain positions of use.
A further medical stapling device is disclosed in U.S. Pat. No. 4,185,762. This device teaches a relatively simple structure wherein staples are moved along a track between grooved rails by a drive member having spaced lugs which are moved into engagement with the staples for advancing them along the track and simultaneously forming a first staple about an anvil. Rearward movement disengages the lugs away from the track so as to position the driver and its lugs for its next stapling cycle or sequence of continued operation.
U.S. Pat. No. 4,202,480 deals with a medical stapler provided with a device which leaves the ram across the staple in the opening to prevent another staple from being fed (double feeding) into the channel if manual activation of the stapler is discontinued before staple ejection. Also the stapler includes means for producing a "click"when the driver ram is moved fully to its eject position to provide both a tactile and an audible indication of the closing of a staple around the anvil.
Another U.S. Pat. No. 4,256,251 teaches a surgical stapler having a magazine or cartridge of staples secured to a base by spring clips and a pair of toggle-joint linkage handles which serve to drive a staple forming ram and bend a staple around the anvil. When pressure on the handles is released slightly, the anvil then is slid out from under the top of the staple.
Other skin staple cartridges such as U.S. Pat. No. 4,127,227 employ a staple cartridge embodying a belt system carrying a plurality of staples and ramp means for singly moving the staples out of the belt and into the plane of the pusher. In the surgical stapler of U.S. Pat. No. 3,873,016, the staple is pushed from the magazine into the driver chamber where it is engaged by the driver and pushed down the chamber to the anvil where it is deformed. Such a stapler also includes ratchet means for preventing a second staple from being fed into the guide while the one ahead of it is still being formed and yet to be ejected.
It is, therefore, a principle object of the invention to provide a unique and novel medical stapler for stapling skin or fascia.
Another object of the invention is to provide an entirely new stapler design which improves visibility at the suture or wound site, and control in the positioning or staple placement. A further object of the invention is to provide an improved skin stapler which has a slender, curved nose section and a closed handle and trigger portion, which are designed to function in an idealized manner with the human hand when in a clasped condition as in the case when pulling the trigger.
Yet another object of the invention is to provide a further improved skin stapler incorporating a driving mechanism which exhibits high driving forces within a confined area, but yet the manual force required to activate and drive the mechanism is small and easily and comfortably handled.
A still further object of the invention is to provide a skin stapler of the disposable type and one which holds a sufficiently large number of stored staples so that in most routine applications where the staples are used, switching instruments when the staples are exhausted is kept to a minimum.